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561.
福建沿岸海域赤潮发生特点及防治措施 总被引:17,自引:2,他引:17
根据多年来福建沿岸海域发生赤潮的情况及相关资料,概述了该海域赤潮发生的主要趋势、时间、区域、种类和危害等特点,分析和讨论了赤潮发生的自然因素和人为因素;并指出赤潮防灾和减灾工作中存在的主要问题是海洋综合管理力量薄弱,海洋法律法规不够健全,海洋执法能力有待加强,海洋事业经费投入不足.在此基础上提出了防治福建沿岸海域赤潮灾害的如下措施和建议:进一步调查和研究赤潮发生的类型并分析其主要成因;建立健全福建省近岸海域环境监测网络和海洋环境监测系统,大力开展具有福建区域特色的赤潮生物及其有害赤潮发生机理等科学研究;控制陆源污染,减少含氮污染物的排放总量和入海量,提倡和推广使用农家肥,提高生活污水的处理效率;认真研究和分析港湾的环境容量,合理开发福建的海水养殖业;加强围填海等涉海工程对海水动力学影响的研究,以及加强对船舶压仓水等带来外来赤潮生物影响的研究等. 相似文献
562.
563.
Argo drifters provide information of the vertical structure in the water column and have a potential for the improvement of
understanding phytoplankton primary production and biogeochemical cycles in combination with ocean color satellite data, which
can obtain the horizontal distribution of phytoplankton biomass in the surface layer. Our examples show that using Argo drifters
with satellite-measured horizontal distribution of phytoplankton biomass at the sea surface allow an improved understanding
of the development of the spring bloom. The other possible uses of Argo drifter are discussed. 相似文献
564.
The northward migration of spring bloom was observed in the Sea of Japan from April to May 1997 by the Ocean Color and Temperature
Scanner (OCTS) on board the Advanced Earth Observing Satellite (ADEOS). This phenomenon is well simulated with a numerical
ecosystem model coupled with a hydrodynamic model. The hydrodynamic model is the Geophysical Fluid Dynamics Laboratory (GFDL)
Modular Ocean Model (MOM). The ecosystem model consists of five components: dissolved inorganic nitrogen (DIN), dissolved
inorganic phosphorus (DIP), phytoplankton, zooplankton and detritus. Results of the numerical ecosystem model suggest that
the mesoscale development of the spring bloom in the Sea of Japan is related to that of sea water temperature, and that the
bloom is limited by the depletion of DIN.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
565.
Cultural eutrophication in the Changjiang (Yangtze River) plume: History and perspective 总被引:18,自引:0,他引:18
The Changjiang (Yangtze River) is known to contribute significantly to the eutrophication that has caused drastic changes to the ecosystem of the East China Sea. However, evidence for historical changes in nutrient concentrations and composition and the consequent effects on the ecosystem in the coastal water is sparse. In this paper we present some long-term data for nutrient concentrations and Si:N:P ratios in the freshwater and the river plume and the long-term response of the ecosystem structure in the river plume. These data reveal increases in the dissolved inorganic nitrogen and phosphate concentrations in the Changjiang freshwater by a factor of five from the1960s to the end of the 1990s and a reduction in dissolved silicate by two thirds over the same period. Concomitantly, an increase in DIN concentration and a reduction in silicate concentration both by a factor of two were observed in the surface water of the Changjiang plume. As an ecological consequence to such nutrient changes, the chlorophyll a concentration increased by a factor of four since the 1980s and harmful algal blooms increased rapidly since 1985 in the Changjiang estuary and adjacent sea areas. The macrozoobenthic biomass decreased sharply from the mid 1980s to the present, suggesting that the Changjiang estuary has been in a high eutrophication state since that time. We predict that, due to the continuously increasing nutrient pressure, the symptoms of eutrophication associated with nutrients will worsen in the Changjiang plume in the near future. 相似文献
566.
567.
Donat Petricioli Tatjana Bakran-Petricioli Damir Vilii Antonieta Poar-Domac 《Marine Ecology》1996,17(1-3):373-382
Abstract. In late summer and early autumn of 1989 benthic mortality in the upper part of Krka estuary extended from the Skradinski buk waterfalls to approximately 5 km downstream. Dead benthic organisms were found on the bottom at depths of up to 4.5 m. During August, a freshwater phytoplankton bloom was recorded in Visovac lake (which supplies the Skradinski buk waterfalls). The green tide in the lake was composed of up to 11.9 million cells. 1- -1 , predominantly of Synedra acus and Dinobtyon sertularia . At that time the maximal total inflow of phytoplankton cells through the waterfalls was approx. 0.41 S-I (38000 1. d-1 ). Cells of these two species died after reaching the salt wedge and the cummulative effect of their decomposition apparently caused an oxygen demand sufficient enough to trigger the benthic mortality. Due to the water mass dynamics, the spreading of mortality downstream was slow (from August to October, approx. 5 km). Certain benthic fishes (like Gobius sp.) were observed on the bottom of the affected area in mid-October 1989. 相似文献
568.
M. V. S. GUPTHA Ran adip BANERJEE Lina P. MERGULHAO Priyanka BANERJEE G. PARTHIBAN Manish TEWARI 《《地质学报》英文版》2007,81(4):614-621
Planktic foraminifera from the calcareous substrate of a ferromanganese crust in the Vityaz Fracture Zone (VFZ), Central Indian Ridge were studied to reconstruct the early Pliocene paleoceanography of this region. Eleven species of planktic foraminifera were encountered, among them Globorotalia menardii, Neogloboquadrina dutertrei, Globigerina bulloides and Globigerinoides tuber are prominent. Predominance of N. dutertrei in the top 3 cm of the carbonate substrate is attributed to an influx of fresh water which eventually triggered their productivity by increasing the nutrient level. The presence of G. bulloides and G. menardii in significant proportions in deeper layers suggests the prevalence of open ocean upwelling. The bulk chemical compositions of the substrate at different depth intervals indicates higher enrichment of trace metals in the upper sections which could have been supplied through oceanic water by the chemical weathering of terrestrial matter during the peak of Pliocene Asian monsoon. Thus, it is concluded that during the early Pliocene the biogenic components of the substrate were distinctly contributed by both upwelling and productivity triggered by an influx of fresh water originating from the intensification of the Asian monsoon during the early Pliocene Period. 相似文献
569.
Mirko Dreßler Thomas Hübener Solvig Görs Petra Werner Uwe Selig 《Journal of Paleolimnology》2007,37(2):205-219
During monthly investigations from 1996 to 2000, a hypolimnetic layer of phototrophic sulphur bacteria (Chromatium spp.) were observed in Lake Dudinghausen, a small dimictic lake in northern Germany. This paleolimnological study was initiated
to detect if the occurrence of sulphur bacteria was related to cultural eutrophication or reflected natural conditions. Therefore,
diatoms, algal pigments, okenone, geochemical proxies, and 210Pb and 137Cs were used in four sediment cores to investigate historical changes in trophic development, hypolimnetic redox conditions,
anoxia and phototrophic sulphur bacteria abundances. Fossil diatoms, pigments, the ratio of chlorophyll derivatives to total
carotenoids and the ratio of chlorophyll a to its derivatives suggest two phases of eutrophication coupled with hypolimnetic anoxia over the last ~80 years: a first
phase from about 1923–1932 and a second from 1952 to 1982. In the first phase the ratios of Fe–Mn as well as Fe–Ca increased,
suggesting seasonal anoxia. However, hypolimnetic anoxia was only weak because low levels of okenone suggest no mass development
of sulphur bacteria. In contrast, sulphur bacteria increased during the early stages of the second eutrophication phase, suggesting
increased temporal and spatial hypolimnetic anoxia. Surprisingly, the ratios of Fe–Mn as well as Fe–Ca decreased during this
time. Possibly Fe, Mn and Ca were equally reduced through the intense anoxia. In the final stage, sulphur bacteria decreased
again. As these bacteria need both anoxic conditions and a certain amount of light, the increased nutrient load probably led
to low Secchi depth and therefore insufficient light conditions. In more recent years, diatoms and pigments suggest a decrease
in nutrient levels. A second mass development of sulphur bacteria occurred, probably due to improved light conditions and
continued anoxia in the upper hypolimnion. We conclude that the recent development of phototrophic sulphur bacteria do not
represent natural conditions in Lake Dudinghausen. Furthermore, the upper sediments contain a completely new diatom flora
that never occurred in older sediments of Lake Dudinghausen. Therefore, nutrient levels may eventually reach natural conditions,
however they may not represent biological background reference conditions. 相似文献
570.
Iron and phosphorus limitation and their combined effects on the growth and development of Prorocentrum micans Ehrenberg (Dinophyceae) and Cryptomonas sp. (Cryptophyceae) have been studied. The growth status of these algae at different Fe and P levels is quantitatively analyzed
through lab-culture experiments. Results show that Fe starvation can misalign chloroplast lamellas, and metamorphose and twist
thylakoid, leading to a retarded growth rate. The combined effects of Fe and P can accelerate their growth, and an optimum
culture condition to maintain the maximum growth rate is a combination of 0.05 μM Fe and 50 μM P. Algal uptake of Fe and P
are synergistic. Their cellular concentrations bear significant correlations (r = 0.9979 for Cryptomonas sp. and 0.9938 for P. micans; P < 0.01) and correspondingly the molar P:Fe ratios are ∼160:1 and ∼356:1, respectively. These findings will provide novel
insights for revealing the crucial factors controlling the occurrence of algal blooms. 相似文献